1. Field of invention
The present invention is in the field of devices for the protection of banknotes, documents of value, or articles in general. It concerns a printed image comprising oriented pigment particles. The image according to the invention shows a dynamic visual motion effect upon tilting, such that one part of the image appears to move in a different plane than the rest.
2. Discussion of Background Information
Devices for the protection of documents, which display a visual motion effect upon tilting, have been disclosed in U.S. Pat. No. 7,738,175 by Steenblik et al. The devices comprise a lenticular array, embodied in a plastic foil or the like, which is associated with microprinted indicia on the document, e.g. through an affixing of the said foil to the document. The disclosure of this document is expressly incorporated by reference herein in its entirety.
Other types of devices for the protection of documents, which display visual motion or “3-dimensional” optical effects, have been disclosed in US 2004/0051297 and in the corresponding international application WO 2004/007095, as well as in WO 2008/009569. These effects are based on surface coatings comprising oriented pigment particles, whose orientation changes gradually across the coated surface. The disclosures of the above-described documents are expressly incorporated by reference herein in their entireties.
According to WO 2004/007095, a first visual effect, called “Flip-Flop” effect (FIG. 1a), is based on a pigment orientation imitating a positively (i.e. towards the observer) curved surface across the coating. The observer sees a specular reflection zone, which moves with the rotation sense of tilting. The disclosure of this document is expressly incorporated by reference herein in its entirety.
According to WO 2004/007095, a second visual effect, called “Rolling Bar” effect (FIG. 1b), is based on a pigment orientation imitating a negatively (i.e. away from the observer) curved surface across the coating. The observer sees a specular reflection zone, which moves against the rotation sense of tilting. The disclosure of this document is expressly incorporated by reference herein in its entirety.
US 2005/0106367, a continuation in part of US 2004/0051297, further discloses a “double rolling bar”. Upon tilting the document the two “rolling bars” seem to move against each other. Also disclosed is a “double-tilt” feature, wherein, upon tilting the document, a bright zone switches from one part of the document to another. The disclosures of these documents are expressly incorporated by reference herein in their entireties.